Atmosphere and weather

Question 1

Factors affecting diurnal energy budget

Answer 1

Insolation, reflected solar radiation, surface absorption, latent transfer, sensible heat transfer and long wave radiation.

Question 2

Incoming solar radiation (Insolation)

Answer 2

Incoming solar energy that reaches the Earth’s atmosphere and surface.

Question 3

Surface absorption

Answer 3

Occurs when energy reaches the Earth’s surface, which heats up.

Question 4

Latent heat transfer

Answer 4

Occurs when water evaporates from a moist land surface or from open water, moving heat from the surface to the atmosphere.

Question 5

Sensible heat transfer

Answer 5

Moves heat from warmer to colder objects by conduction when they are in direct contact.

Question 6

Long wave radiation

Answer 6

Radiation emitted from Earth.

Question 7

Reflected solar radiation (Albedo)

Answer 7

A measure of how much light that hits a surface is reflected without being absorbed.

Question 8

Excesses and deficits of the latitudinal pattern of radiation

Answer 8

Excess: positive radiation budget in the tropics. Occurs because insolation is so concentrated.

Deficit: negative radiation budget at higher latitudes. Insolation has a larger amount of atmosphere to pass through, there is more chance of reflection back to space, and rays are less concentrated.

Question 9

Wind belts

Answer 9

Air will move faster closer to the poles, due to the distance between earths axis of rotation and the air. This fast-moving air produces jet streams. Air closer to the equator will move slower. In addition, faster moving air occurs at high pressure zones, due to centrifugal force – because pressure and Coriolis force work together.

Question 10

Ocean currents

Answer 10

Surface currents caused by prevailing winds. Clockwise rotation in N.Hemisphere, and anticlockwise in S.Hemisphere. Water piles into domes and due to Earth’s rotation, water is piled up on western edge of ocean basins – return flow is a narrow, fast current (gulf stream). Warm currents from equatorial regions raise temps in polar regions. Warm surface causes low pressure, air moves from high to low, so water moves from cold to warm; and winds push warm into warm, exposing cold deep water. Process repeats.

Question 11

Variations in temperature

Answer 11

Air temperature decreases with altitude, as air is thinner, contains less moisture and is therefore less able to absorb longwave radiation.

Question 12

Variations in pressure

Answer 12

Air is driven by the pressure gradient – air moves from high to low pressure. Air moves as per the 3-cell model, where high pressure is caused where air sinks to the ground, leaving space for adjacent air at high altitudes to move over and add to the weight of the sinking air mass. Since earth is spinning, winds blow at angles due to the Coriolis force.

Question 13

Coriolis force

Answer 13

Air masses are deflected due to Earth’s easterly rotation. Air moving from high pressure to low pressure in the N. Hemisphere is deflected to the right, and to the left in the S.Hemisphere acts at right angles to wind direction.

Question 14

Geostropic balance

Answer 14

Between Coriolis Force and pressure gradient, produces resultant wind – Geostrophic wind. In N. Hemisphere, wind blows anti-clockwise around low pressure and clockwise around high pressure. ­

Question 15

Friction

Answer 15

Reduces geostrophic force and wind speed, so pressure gradient is no longer balanced by the Coriolis force. Makes air more likely to move to low pressure zones.

Question 16

Atmospheric moisture processes

Answer 16

Evaporation, condensation, freezing, melting, deposition and sublimation.

Question 17

Evaporation

Answer 17

Occurs when vapour pressure of a water surface exceeds that in the atmosphere. Sped up by: low initial air humidity, heat and strong wind.

Question 18

Condensation

Answer 18

Further cooling below dew point temperature, or when an air mass reaches saturation – turns water vapour into a liquid water. When hygroscopic condensation nuclei are present.

Question 19

Freezing

Answer 19

Liquid water changes into a solid once temperature falls below 0°C.

Question 20

Melting

Answer 20

The change of state from solid to liquid above 0°C.

Question 21

Deposition

Answer 21

Transition from water vapour to ice, with no intermediate stage. May deposit on surfaces.

Question 22

Sublimation

Answer 22

Transition from ice to water vapour, with no intermediate stage. Might occur in low humidity.

Question 23

Causes of precipitation

Answer 23

Convectional, frontal, orographic, radiation cooling, frontal inversion and subsidence inversion.

Question 24

Convectional

Answer 24

Land is heated and so air directly above becomes less dense, rises and cools. As air rises further, latent heat is released, powering the ascent. When condensation occurs, clouds form, precip falls.

Question 25

Frontal

Answer 25

Warm air meets cold air. Less dense warm air can’t push cool air out of the way, so is forced over the colder air. Warm air rises, cools and condenses, forming a cloud and therefore rain. Centre of low pressure where two air masses intersect.

Question 26

Orographic

Answer 26

Pressure force strong enough to force air to move over a barrier. Air rises, it cools and reaches dew point where cloud forms and precipitation falls. Windward side is called the ‘rain slope’, lee slope named ‘rain shadow’ as unsaturated air sinks and warms. Hill fog occurs when the forced ascent produces a thin stratiform cloud. Unstable air (rising temp is warmer than the air rising into) causes continued rising, instead of falling down the lee slope.

Question 27

Radiation cooling

Answer 27

Cloudless night, so ground loses heat rapidly by returning radiation to space. Little wind present, air remains in contact with valley sides to cool by conduction, sinks to bottom of valley. Bottom of valley has a source of moisture.

Question 28

Frontal inversion

Answer 28

Colder, denser air mass descends, forming warmer air above. Barrier created where the two meet that prevents warm air parcels from rising through to the warm air.

Question 29

Subsidence inversion

Answer 29

Air moving upwards experiences adiabatic cooling, due to pressure decrease. This air falls, becomes denser and warms, warm air reaches a cooler layer of unstable air, and a temperature inversion is created.

Question 30

Types of precipitation

Answer 30

Rain, hail, snow, dew, and fog.

Question 31

Rain

Answer 31

Liquid water droplets heavy enough to fall to the ground. Between 0.5mm and 5mm. Drizzle is rainfall less than 0.5mm. Varies in amount, intensity, duration.

Question 32

Hail

Answer 32

Raindrops carried to freezing level inside a cumulonimbus cloud, and freeze. Hailstones then collide with supercooled water freezing on impact. Rising and falling in the cloud causes repeated melting and freezing until the hailstone is heavy enough to fall.

Question 33

Snow

Answer 33

Snow crystals form when temp is below freezing, and water vapour turns solid. Heaviest snowfall occurs when warm moist air is forced to rise in orthographic or frontal rainfall, as very cold air contains limited moisture.

Question 34

Dew

Answer 34

Deposition of water on a surface that occurs in anticyclonic systems. Rapid radiation cooling causes ground temperature to hit dew point and condensation/direct ground precipitation occur.

Question 35

Fog

Answer 35

Forms as a result of radiation cooling. When sun rises, fog lifts, possibly causing smog to form under an inversion layer (cold air trapped by warm air above it). Fog is common over the sea in autumn and spring.

Question 36

Greenhouse effect

Answer 36

Greenhouse gasses such as water vapour, carbon dioxide and methane allow shortwave radiation to penetrate, but prevent longwave. This traps radiation inside the atmosphere, causing temperature to rise.

Question 37

Methane

Answer 37

Cattle produces 75m tonnes and wetlands 150m tonnes. Methane released as perma-frost melts.
(Increases at 0.5-2% per year).

Question 38

CFCs

Answer 38

Destroy ozone, allowing more insolation to enter the atmosphere. (Increases 6% each year).

Question 39

Nitrous oxides

Answer 39

300x more powerful than CO2, from fertilisers, burning fossil fuels and vegetation. (Increased by 8%).

Question 40

Carbon dioxide

Answer 40

Increased fossil fuel burning and deforestation – which increases emissions as well as removing trees that reduce emissions. 5 gigatons of fossil fuels were burnt in 1980 – 1 ton burnt = 4 tons CO2 emitted.

Question 41

Causes of global warming

Answer 41

Fossil fuel burning is directly related to the global temperature increase, deforestation and urbanisation has resulted in more, much darker surfaces, so the ground absorbs more radiation, which is released back to the atmosphere, heating it.

Question 42

Impacts

Answer 42

Sea levels, warming oceans, storm activity, agriculture, drought, disease, wildlife, tourism and cost.

Question 43

Sea levels

Answer 43

200m people could be displaced, 4 million km2 of land threatened by floods, 200m at risk from flood/droughts. Rise by 2100 is expected to be 26-77cm. 570 cities exposed, contamination of drinking water (salt infiltrates groundwater and aquifers), millions of coastline miles under threat.

Question 44

Warming oceans

Answer 44

50% increase in marine heatwaves this decade. 1°C fluctuation causes plankton and coral to stress and bleach (spit out symbiotic algae and die). First 700m of ocean absorbs most heat.

Question 45

Storm activity

Answer 45

More frequent and intense hurricanes, tornadoes etc… Floods have causes >500,000 deaths and affected 2.8bn globally, with $8bn in damages in the USA.

Question 46

Agriculture

Answer 46

USA’s grain belt will decrease, China’s growing season will increase, Northward shift for timber and crop production. 35% drop in African produce if 3°C temperature rise. $10bn in losses in Texas and Oklahoma in a year due to failed crops.

Question 47

Drought

Answer 47

Reduced rainfall in Europe and USA will expose 4bn to water shortage risks.

Question 48

Disease

Answer 48

60 million more people exposed to Malaria, as mosquitos breed faster in the heat.

Question 49

Wildlife

Answer 49

40% of species will become extinct at +2°C.

Question 50

Tourism

Answer 50

Previously undesirable areas may become tourist hotspots, and likewise for desirable places becoming undesirable.

Question 51

Cost

Answer 51

1 tonne CO2 causes £45 of damage. Solving the effects could cost 5-20% of each country’s GDP, whereas action now may only cost 1% of each GDP.